What does Luke 18:20 mean?

A wealthy young man, important in his community, asks Jesus how to inherit eternal life. It's evident he is sincere; he's not looking for a theological argument. When he poses his question, he calls Jesus "Good Teacher." Jesus counters that only God is good (Luke 18:18–19). The term used by both the young ruler and Jesus is based on the root word agathos. It means to have a good nature, be useful, be pleasant and agreeable, to be honorable. All these characteristics are most evident within interactions with other people.

Jesus now builds on that response. He asks the man if he follows the Ten Commandments. Specifically, the commandments referring to how to treat other people. Notably, Jesus skips the last—do not covet—perhaps because the man is rich and likely doesn't covet others who live in the same town. This omission may also be to set up the conclusion of Jesus' point (Luke 18:22–23). This list resembles the one given by the Pharisee in Jesus' previous parable: "God, I thank you that I am not like other men, extortioners, unjust, adulterers, or even like this tax collector" (Luke 18:11).

The young man affirms that he has kept these commandments; he is an honorable, pleasant person to other people. Jesus knows this is true (Mark 10:21). And yet, being agreeable and useful is not enough to merit eternal life. There is no standard of good that is enough.

So, Jesus pushes him to the level of good He knows he cannot reach: "Sell all that you have and distribute to the poor" (Luke 18:22). The man walks away, very sad. The idea of being poor repulses him more than Jesus and His message attracts. The man can't understand that what he thinks of as "goodness" is garbage compared to God (Philippians 3:8–11). What he needs is the proverbial tax collector's total dependence on God's mercy (Luke 18:13–14).